Most new words are made up from other earlier words; language-making is a conservative process, wasting little. When new words unfold out of old ones, the original meaning usually hangs around like an unrecognizable scent, a sort of secret. There are two immense words from Indo-European, gene and bheu, each a virtual anthill in itself, from which we have constructed the notion Of everything. At the beginning or as far back as they are traceable, they meant something like being. Gene signified beginning, giving birth, while bheu indicated existence and growth. Gene turned itself successively into kund jaz (Germanic) and gecynd (Old English), meaning kin or kind. Kind was at first a family connection, later an elevated social rank, and finally came to rest meaning kindly or gentle. Meanwhile, a branch of gene became the Latin gens which emerged as genus, genius, genital, and generous; then still holding on to its inner significance it became 'nature' (out of gnasci). While gene was evolving into 'nasture' and 'kind' bheu was moving through similar transformations. One branch became the English word 'build'. It also moved into Greek, as phuein, meaning to bring forth and make grow; then as phusis, which was another word for nature. Phusis became the source of physic which at first meant natural science and later was the word for medicine. Still later, physic became physics. Both words, at today's stage of their evolution, can be taken together to mean, literally, everything in the universe. You do not come by words like this easily; they cannot just be made up from scratch. They need long lives before they can signify. 'Everyting,' C. S. Lewis observed in a discussion of the words, 'is a subject on which there is not much to be said.' The words themselves must show the internal marks of long use; they must contain their own inner conversation.The passage is mainly concerned with ______.A．how to coin new wordsB．where to trace the origin of languageC．the evolution of wordsD．language and nature